Low temperature storage container



J. D. LOUDON Jan. 17, 1967 LOW TEMPERATURE STORAGE CONTAINER 4 Sheets-Sheet 2 Filed July 15, 1964 INVENTOR. Jo hn D. Loudon ATTORNEYS Jan. 17,

Filed July 15, 1964 1967 J LOUDQN 3,298,185

LOW TEMPERATURE STORAGE CONTAINER 4 Sheets-Sheet 5 INVENTOR. John D. Loudon ATTORNEYS LOW TEMPERATURE STORAGE CONTAINER Filed July 15, I964 4 Sheets-Sheet 4 INVENTOR. John D. Loudon ATTORNEYS United States Patent Ofiiice 3,298,135 Patented Jan. 17, 1967 3,298,185 LOW TEMPERATURE STQRAGE CONTATNER .lohn D. London, Eoulder, (1010., assignor to Cryogenic Engineering (Iompany, Denver, (Zola, a corporation of Colorado Filed July 15, 1964, Ser. No. 382,919 8 tilaims. (Cl. 6248) This invention relates to low heat inleak storage containers, sometimes referred to as low temperature storage containers, and more particularly to improvements in double walled, vacuum insulated containers having an inner vessel arranged to be filled or partially filled with a liquid refrigerant such as liquefied gas.

Low temperature or low heat inleak vessels are utilized for many applications in the storage, preservation or shipping of many different types of materials requiring a very low temperature environment. In the conventional construction these containers are double walled with the space between the inner and outer vessels having insulation and being evacuated. Generally, such low heat inleak vessels have a single access opening, and this opening is preferably a long necked opening extending from the exterior of the outer container to the interior of the inner container. This provides a long tubular access conduit connecting the inner vessel with the exterior of the outer vessel, generally leaving a space which is considered a vapor space around the neck in the inner vessel which is above the main storage capacity of the vessel.

According to the present invention, means are provided for increasing the refrigerant capacity of a double walled, vacuum insulated container, particularly where the inner vessel is arranged to be filled or partially filled with a liquid refrigerant. By utilizing the invention such a container may be utilized for wet storage where the container is filled with refrigerant or for dry storage where the container has no liquid refrigerant standing in the inner vessel. The invention provides increased capacity for refrigerant in the Wet system, as well as providing refrigerant for a dry system. The invention provides for arranging a refrigerant absorbing material or media in the non-utilized spaces in the inner container. The refrigerant liquid to be absorbed into the absorbing media thereby increases refrigerant capacity without decreasing the capacity of the inner vessel for the stored material and without increasing the dimensions of the vessel.

Included among the objects and advantages of this invention is to provide a means for increasing the refrig erant capacity of double walled, vacuum insulated containers without increasing the overall dimensions of such containers.

Another object of the invention is to provide improved refrigerant capacity in double walled vacuum insulated containers so that the container may be utilized as a dry shipping container. 7

Another object of the invention is to provide means for increasing the refrigerator capacity of a double walled vacuum insulated container by providing refrigerant absorbent material in the non-utilized spaces of the inner container.

A still further object of the invention is to provide a double walled vacuum insulated container as a dry storage container with suificient refrigerant absorbed into absorbing medium in the non-utilized portions of the container to provide greatly increased refrigeration capacity for stored material. 7

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustrations in which:

FIG. 1 is an elevational view partially in section of a double walled vacuum insulated container provided with an absorption medium in the non-utilized spaces of the container in accordance with the invention;

FIG. 2 is an elevational view partially in section of a double walled vacuum insulated container provided with a vapor space absorbing medium for increased capacity of absorption media according to the invention;

FIG. 3 is a cross-sectional view of a conventional double walled vacuum insulated container for storing a plurality of small containers including a long, low-heatinleak access neck; and

FIG. 4 is a cross-sectional view of a similar type of container for storage of small containers provided with refrigerant absorbing media in unused portions of the container in accordance with the invention.

In the illustration of FIG. 1 a double walled vessel is shown utilizing refrigerant absorbing media of the invention. This includes an outer container 1 which encloses an inner container 2 leaving a space between them. The space may be filled with an insulating material 4, as shown, and evacuated, or merely evacuated without the insulation. A closure 5 is provided for an opening 6 through which the space 4 is evacuated. The insulation may be any suitable type, such as opacified powder, laminar, etc., as is conventional in the industry. An elongated tubular conduit 3 provides access from the exterior of the outer member 1 to the interior of the inner vessel 2). The inner vessel 2 is interconnected with the tubular conduit 3 at 7 which extends into the inner vessel, leaving a substantial vapor space 14 between the top Q of the inner vessel and the bottom 7 of the tubular conduit 3. A cap or other cover means 10 is provided for the conduit to reduce the heat loss into the inner container.

The elongated access tube is a conventional means to reduce the heat loss which would otherwise occur with a short neck due to the short heat path through the neck tube and associated plug or cap. Absorbent getter 11 may be placed in the space on top 9 of the inner container to further assist in maintaining the established vacuum.

Refrigerant absorbing media 12 is placed around the periphery of the inner container 2 and it extends up into the vapor space around a neck portion 9a adjoining the tubular inlet 3. The absorbing media is maintained in position by means of a tubular perforate plate 15 and a top retaining perforated member 16. These two retaining members hold the absorbing media in place including the vapor space around the neck portion 9a. A short perforated tubular 'wall 17 provides passage from the interior of the container into the tubular conduit 3.

The absorbing media may be glass fiber paper, or other absorbent such as charcoal, silica gel, molecular sieves, and such similar absorbing media. The means for holding the absorbent in place may be a perforated plate, screen or the like depending on the character of the absorbent. The refrigerant which is used in such vessels is normally a liquefied gas such as, for example, liquefied nitrogen, liquefied helium, and the like, the choice of the liquid being determined by the temperature requirement. The liquefied gas is placed in the container through the access conduit 3 and the liquid passes through the perforate plate 15 into the absorbing media 12 along the vertical wall of the container. By capillary action the liquid may pass up along the wall into the space around the neck, or for smaller vessels tipping will flow the fluid into contact with the absorbent at the top.

As an example of the increased capacity in a conventional container, one form is shown in FIG. 1; an outer vessel having a diameter of 17 inches and being 21 inches high has an inner vessel with a capacity of 40 liters. This measured capacity extends up to the bottom 7 of the access neck 3. Without the absorbent media this is the ultimate capacity since the vapor space around the neck cannot be available for liquid. When liquid reaches the neck, the space 14 becomes a vapor trap which prevents further filling of the inner vessel itself. The volume of the vapor space is about 8.8 liters and, by placing the absorbing media 12 into the space 14, additional capacity is available. The refrigerant capacity of the inner vessel is increased from 40 to about 47 liters, or an increase of available refrigeration capacity of about 17.5%.

In FIG. 2 a similar type vessel is utilized with the absorbent material only in the vapor space. In this case the vessel includes an outer container 20 and an inner container 21 with a space 22 therebetween which is provided with a closure 23 for evacuating the space and contained insulation. The construction is similar to that of FIG. 1 including an elongated access conduit 24 which terminates below the top 25 of the inner container 21 while the lower part of the neck 26 extends a substantial distance into the container 21.

An absorbing medium 27 is placed in the vapor space between the lower part of the neck 26 and the top of the container 25. A perforate wall 28 having a central orifice 29, which mates with the access opening 24, holds the absorbing medium in the space around the neck.

For use of the device shown in FIG. 2 the liquid refrigerant is poured into the container until it reaches the neck, Where substantially no additional refrigerant may be added. By tilting the container, the liquid passes through the porous wall 28 into the absorbent media until it becomes saturated. Then by returning the container to an upright position, additional liquid can be poured into the container filling it to the neck. This form is highly useful for wet storage since it increases refrigerant capacity within the vapor space and permits retention of additional liquid in the storage area.

In both cases, the absorbing medium acts as a reservoir for the refrigerant liquid so that the container may be utilized in many different ways. Where it is desired to use either container as a dry storage container, the absorbing material may be completely saturated with the refrigerant liquid and any remaining liquid poured from the container. The absorbing medium retains additional liquid where the vessel is used for wet storage.

Another double walled vacuum container is shown in FIG. 3 which typifies earlier practice. Such a container has been described and claimed in the copending application of Reynolds et al., Serial No. 138,758, filed September 18, 1961, now abandoned, for Cryogenic Type Thermally-Insulated Container and assigned to the assignee of this application. Such a vessel includes an outer member 3%) and an inner container 31 having a space 32 filled with insulation therebetween. The outer container includes an elongated neck portion 33 through which a tubular access conduit 34- passes into the inner container 31, providing a space therebetween which is an extension of space 32. The space 32 may be filled with an insulating material which is evacuated. The lower part 35 of the access conduit 34 extends below the top 36 of the inner container so that a vapor space occurs between the bottom of the access conduit and the top of the container. A closure 37 is provided for the access conduit and it includes insulating plugs 38 secured together to fill the conduit when in place.

A rotary shelf or tray 4a having a plurality of holes 41 is supported from a shaft 42 rotatably mounted on a pedestal 43 by means of a ball bearing 44. The top of the shaft 42 is secured by a bearing set 45 to a top brace or plate 46. Containers 48, each having a shelf supporting flange 49, are arranged to seat in the holes 41 in the shelf. The shelf may be turned to register the containers with the access opening for removal.

FIG. 4 illustrates how the vessel of FIG. 3 may be modified to substantially increase refrigerant capacity without reducing storage capacity. The outer member 3tlx is extended in its upper portion to substantially enclose the neck portion 33x enclosing the elongated access passage or opening 34x. The inner container 31x is spaced from the outer member Stlx with suitable insulation disposed therebetween and the space 32x including the space around passage 34x is evacuated. The lower end 35x of the access passage thus is disposed at a substantial distance below the top 36x of the inner container member 31x and the space 3% therebetween is utilized as refrigerant storage space. The access passage 34x has its upper end enclosed by a cap or closure member 37x, as in FIG. 3.

The rotary shelf Mix and associated shaft 42x again are mounted within the container 31x on a pedestal 43x to provide means for holding a plurality of containers 48x submerged in the stored liquid in container 31x. Shaft 42x is held within bearing assemblies 4.4x and 56x as in FIG. 3. The storage space of the container 31x is separated from the upper refrigerant space lwx by a foraminous partition 53x and a cylindrical foraminous member 50x is disposed within the storage area externally of the path of rotation of member Mix and the suspended cannisters or containers 43x.

Absorbent media 51x is inserted in the space between member 50x and inner container 31x in the storage area and similar media fills space 39x above foraminous member 53x. When the container of FIG. 4 is to be put into service, its interior is filled with low temperature liquid to the bottom of the acess passage 34x, after which the vessel is tilted to allow the liquid to flow into the media in space 39x. When the media no longer takes in liquid, the vessel is returned to its normal upright position and more liquid is introduced to fill the interior to bottom 35x of access passage 34x. This filling leaves the vessel with the same storage capacity as the vessel of FIG. 3, but increases its refrigerant capacity to a substantial degree.

In addition, the vessel of FIG. 4 may be used as a dry storage container by omitting the second filling described above. After the liquid saturates the absorbent material in spaces 39x and 51x, excess liquid is poured from container 31x leaving its storage space as an essentially dry area.

From the foregoing, it will be apparent that the practice of my invention permits use of standard equipment designs having the same external dimensions, with a substantial increase in the volume of low temperature liquid which may be contained as refrigerant, and without any reduction in storage capacity.

While this invention has been illustrated with reference to particular embodiments, there is no intent to limit the spirit or scope of the precise details so set forth except as defined in the apended claims.

I claim:

1. In a low temperature storage container including inner and outer members having an evacuated insulating space between, and having an upper access passage which terminates in the interior of the inner member leaving a vapor space between the inner terminus of said passage and the top inside surface of said inner member, and adapted to contain a a charge of a liquid refrigerant in said inner member, the improvement which comprises a first barrier pervious to liquid refrigerant arranged circumferentially of the storage area, a second barrier pervious to liquid refrigerant separating the storage area from said vapor space, liquid refrigerant absorbing media disposed externally of the circumferential barrier and other liquid refrigerant absorbing media above and supported as the second barrier disposed in contacting relation with the externally disposed media so that liquid refrigerant is transferred by capillary action.

2. In a low temperature storage container including inner and outer members having an evacuated insulation space between, and having an upper access passage which terminates in the interior of the inner member leaving a vapor space between the inner terminus of said passage and the top inside surface of said inner member, and adapted to contain a charge of a liquid refrigerant in the inner member, the improvement which comprises top and side barriers pervious to liquid refrigerant and bordering an interior storage space of the container, and layers of refrigerant absorbing glass fiber paper disposed between said barriers and inner surfaces of the inner member, and said layers bordering the side of the storage area and the top of said area being in contacting relation so that liquid refrigerant is transferred by capillary action.

3. The improvement of claim 2 in which said pervious barriers are perforated plates.

4. The improvement of claim 3 in which said pervious barriers are screen material.

5. A low temperature storage container for storing material therein comprising:

an inner member; an outer member, the space between said inner and said outer member being an evacuated insulating space; an upper access passage terminating in the interior of the inner member and leaving a vapor space between the inner terminus of said passage and the top inside surface of said inner member, the volume below said inner terminus of said passage comprising a storage volume for said material and adapted to receive a charge of liquid refrigerant; a liquid refrigerant adsorbent media disposed in said vapor space and adjacent said storage volume; and a barrier means pervious to said liquid refrigerant,

said barrier means being located between said storage volume and said refrigerant adsorbing media for preventing said adsorbent media from entering said storage volume but permitting said liquid refrigerant to be adsorbed in said media, whereby the material storage containers vapor space is used to store said liquid refrigerant and the refrigeration capacity of said material storage container is increased. 6. The improvement of claim 5 in which said absorbing media is glass fiber paper.

7. A low temperature storage container for storing material therein comprising:

an inner member; an outer member, the space between said inner member and said outer member being an evacuated insulating space; an upper access passage terminating in the interior of the inner member and leaving a vapor space between the inner terminus of said passage and the top inside surface of said inner member, the volume below said inner terminus of said passage comprising a storage volume for said material and adapted to receive a charge of liquid refrigerant;

a liquid refrigerant adsorbing media disposed in portions of said inner member including said vapor space externally of said storage volume;

and barrier means pervious to said liquid refrigerant, said barrier means being located between said storage volume and said refrigerant adsorbing media for preventing said adsorbent media from entering said storage volume but permitting said liquid refrigerant to be adsorbed in said media, whereby the portions of said inner member that are external to said storage volume are used to store said liquid refrigerant so that the refrigeration capacity of said material storage container is increased.

8. A low temperature storage container for storing material therein comprising:

an inner member;

an outer member, the space between said inner member and said outer member being an evacuated insulating space;

an upper access passage terminating in the interior of the inner member and leaving a vapor space between the inner terminus of said passage and the top inside surface of said inner member, the volume below said inner terminus of said passage comprising a storage volume for said material and adapted to receive a charge of liquid refrigerant;

a top barrier member pervious to said liquid refrigerant and bordering said storage volume of said material storage container;

and layers of refrigerant adsorbing glass fiber paper supported on said top barrier so that said glass fiber paper is prevented from entering said storage vo1- ume, whereby the portion of said inner storage container located above said top barrier is used to store said liquid refrigerant and the refrigeration capacity of said material storage container is increased.

References Cited by the Examiner UNITED STATES PATENTS 1,091,461 10/1954 France.

LOUIS G. MANCENE, Primary Examiner.

RAPHAEL H. SCHWARTZ, Examiner. 

1. IN A LOW TEMPERATURE STORAGE CONTAINER INCLUDING INNER AND OUTER MEMBERS HAVING AN EVACUATED INSULATING SPACE BETWEEN, AND HAVING AN UPPER ACCESS PASSAGE WHICH TERMINATES IN THE INTERIOR OF THE INNER MEMBER LEAVING A VAPOR SPACE BETWEEN THE INNER TERMINUS OF SAID PASSAGE AND THE TOP INSIDE SURFACE OF SAID INNER MEMBER, AND ADAPTED TO CONTAIN A CHARGE OF A LIQUID REFRIGERANT IN SAID INNER MEMBER, THE IMPROVEMENT WHICH COMPRISES A FIRST BARRIER PERVIOUS TO LIQUID REFRIGERANT ARRANGED CIRCUMFERENTIALLY OF THE STORAGE AREA, A SECOND BARRIER PERVIOUS TO LIQUID REFRIGERANT SEPARATING THE STORAGE AREA FROM SAID VAPOR SPACE, LIQUID REFRIGERANT ABSORBING MEDIA DISPOSED EXTERNALLY OF THE CIRCUMFERENTIAL BARRIER AND OTHER LIQUID REFRIGERANT ABSORBING MEDIA ABOVE AND SUPPORTED AS THE SECOND BARRIER DISPOSED IN CONTACTING RELATION WITH THE EXTERNALLY DISPOSED MEDIA SO THAT LIQUID REFRIGERANT IS TRANSFERRED BY CAPILLARY ACTION. 